Lecture 4

Question 1

What type of graph is most often used to visualize the relationship between two variables?

Answer 1

scatterplot

Question 2

What are the typical questions answered answered by a scatterplot?

Answer 2

form (linear, quadratic, etc.), strength (weak, moderate, strong) & direction of the relationship (positive or negative) between two variables

Question 3

What is a regression model?

Answer 3

a statistical technique for modeling the relationship between two variables (x & y)

Question 4

What is the x variable?

Answer 4

predictor variable

Question 5

What is the y variable?

Answer 5

response variable

Question 6

Measure of how much two quantitative random variables change together.

Answer 6

covariance

Question 7

What shows the direction in the linear relationship between two variables?

Answer 7

sign of the covariance

Question 8

What is the normalized version of the covariance?

Answer 8

correlation

Question 9

What shows both the direction & strength of the linear relation?

Answer 9

correlation

Question 10

How is population correlation denoted?

Answer 10

p

Question 11

How is sample correlation denoted?

Answer 11

r

Question 12

The correlation always lies between what two values?

Answer 12

-1 and 1

Question 13

Sample covariance formula

Answer 13

[insert image]

Question 14

Population covariance formula

Answer 14

[insert image]

Question 15

Sample correlation formula

Answer 15

[insert image]

Question 16

Population correlation formula

Answer 16

[insert image]

Question 17

What is regression analysis?

Answer 17

set of statistical procedures for estimating the relationship between a response variable (numerical) and predictor variable(s)

Question 18

When the relationship between the response variable and the predictor variable is approximately linear.

Answer 18

simple linear regression (SLR)

Question 19

What is the SLR formula?

Answer 19

y=beta_0 + beta_1x + e [insert image]

Question 20

What is beta_0